1. Technical Field
The present invention generally relates to a securing device, and particularly relates to a clip for attaching a heat sink to an electronic element package for heat dissipation.
2. Related Art
Development of integrated circuit technology has resulted in the enhanced density of very large scale integrated circuits (VLSI) in electronic element packages, such as a central processing unit (CPU). The electronic element package operates at a very high speed. The faster the electronic element package runs, the more it generates heat. The heat generated by the electronic element package not to be removed away in time will lead to an increase of temperature of the electronic element package and result in instability of operation of the electronic element package and occurrence of functional obstacle. Therefore, how to dissipate heat fast and effectively has become a problem that must be resolved before a CPU is applied.
In order to remove the heat generated by the electronic element package, a heat sink is applied to assist dissipating heat, and a clip is used to fasten the heat sink to the electronic element package tightly. The earliest method of securing a heat sink is to use several screws traveling through a printed circuit board (PCB) and the heat sink to couple the heat sink and the electronic element package installed on the PCB. However it is distinctly inconvenient to use screws to mount or remove the heat sink. On the other hand, an accessory tool is needed which results in mounting or removal of the heat sink complicated. Furthermore, it is difficult to keep the contacting forces between the heat sink and the PCB at the positions where the screws are located equivalent to cause the heat sink to intimately contact the electronic element package. The method of using screws is out of application bit by bit. A wire clip has been consequently applied. A wire clip is generally made by bending an elastic metal wire to form a Z-shaped clip with a middle press portion and two clamping arms extending from the press portion. In use, the press portion of the wire clip bears against the heat sink and the clamping arms clamp protrusions of a socket connector on the PCB. However, it is inconvenient to hold the slim elastic hook in use. So, it is not widely used.
A clip in common use at present is illustrated in FIG. 4. The clip includes a body 100 and a hanger 200. The body 100 comprises an elongated curved press portion 120 and a clamping portion 140 extending downwardly from one end of the press portion 120. The hanger 200 is hanged to the other end of the press portion. Two openings 160, 240 for engaging protrusions (not shown) on a socket connector are respectively defined in the clamping portion 140 of the body 100 and the hanger 200. It is an improvement in contrast with the above-mentioned screws and the wire clip. However, it is difficult to engage the hanger 200 with the socket connector after clamping portion 140 engages with the socket connector. Moreover, the hanger 200 is still inconvenient to be held. On the other hand, the clip is mostly located in a groove between two adjacent fins in the middle of the heat sink for preventing the heat sink from moving in a horizontal direction. The groove for receiving the clip occupies the space of the heat sink which would otherwise be occupied by heat dissipating fins. Thus, the clip reduces the heat dissipating surface area of the heat sink and therefore decreases the heat dissipating efficiency of the heat sink.
Along with the continuing development of integrated circuit technology, the size of heat sink is becoming larger and larger corresponding to the continuing increase of heat generated by electronic element package. A larger force is required to be exerted to a heat sink for ensuring firm contact between the heat sink and an integrated circuit package. How to mount firmly and conveniently a large dimension heat sink to a PCB by a small operation force becomes a problem which needs overcoming.
Thus, an improved clip which overcomes the above-mentioned problem is desired.